Physical Address

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Supraclavicular and infraclavicular regions


Core Procedures

  • Excision of a lump from the neck

  • Exploration of the supraclavicular brachial plexus

  • Excision of the first rib

  • Exploration of the infraclavicular brachial plexus

  • Anaesthetic nerve blocks

Surgical surface anatomy

The margins of the posterior triangle, the superior border of the clavicle, the lateral border of sternocleidomastoid and the anterior border of trapezius are all palpable. The upper trunk of the brachial plexus can usually be palpated in the scalene groove and in its anteroinferior course. The pulsation of the subclavian artery may be palpable in the inferomedial angle of the triangle. The various groups of lymph nodes are not usually palpable unless significantly enlarged. In the infra­clavicular region, the deltopectoral groove is easily identified between the inferomedial border of deltoid and the superolateral border of pectoralis major.

Clinical anatomy

Posterior triangle of the neck

The posterior triangle of the neck is bounded by the middle third of the clavicle inferiorly, the posterior border of sternocleidomastoid anteromedially and the anterior border of trapezius posterolaterally. It is divided by the inferior belly of omohyoid into the occipital triangle superiorly and the supraclavicular triangle inferiorly. Its roof consists of skin, a zone of loose connective tissue containing platysma and the three supraclavicular nerves in its lower part, and the deep cervical fascia.

The floor of the occipital triangle is formed by splenius capitis, levator scapulae and scaleni medius and posterior. The floor of the supraclavicular triangle consists of the first rib and scaleni medius and anterior (see Fig. 15.1A ).

The most significant structure in the occipital triangle is the access­ory nerve, which emerges from sternocleidomastoid, crosses levator scapulae obliquely and enters the deep surface of trapezius, where it is vulnerable to damage when the mid portion of the posterior triangle is being explored. Other structures encountered include branches of the cervical plexus, the transverse cervical vessels and the more proximal elements of the brachial plexus.

The supraclavicular triangle contains the three trunks of the brachial plexus; the suprascapular nerve (which arises from the upper trunk); the subclavian artery; and the suprascapular vessels. The latter generally lie behind the clavicle and pass posterolaterally to join the suprascapular nerve in its path towards the suprascapular notch ( Fig. 37.1 ). The subclavian vein does not usually appear in the triangle but may occasionally be encountered in its anteroinferior corner, where it lies in front of scalenus anterior.

Fig. 37.1, Vessels and nerves of the neck, left lateral view. The left sternocleidomastoid, the greater part of the infrahyoid group of muscles, numerous vessels and the medial part of the clavicle have all been removed in order to expose deeper structures. Compare with Fig. 15.3B , which shows a more superficial level of dissection. The letters V, VI, VII, VIII refer to the ventral primary rami of C5, C6, C7 and C8, respectively.

Lymph nodes lie along the posterior border of sternocleidomastoid (jugular groups) and in the supraclavicular fossa (transverse cervical or supraclavicular group). Lymph nodes in the occipital triangle are present around the spinal accessory nerve (posterior triangle or spinal accessory group). Together they form the lateral cervical group. Consequently, an enlarged lymph node can present almost anywhere in the posterior triangle.

Virchow's node is the enlargement of a node in the left supra­clavicular fossa, where the thoracic duct empties into the left subclavian vein. Classically, it is the result of metastasis from a gastric malignancy, although it may be caused by spread from other thoracic, intra-abdominal or pelvic tumours. Occasionally, it is due to lymphoma. Its enlargement is known as Troisier's sign. It can be distinguished from a reactive lymphadenitis by fine needle aspiration cytology.

Brachial plexus

The brachial plexus is formed by the ventral (anterior) primary rami of C5 to T1. The roots of C5 and C6 join to form the upper trunk. The upper trunk gives rise to the suprascapular nerve, which passes posterolaterally through the suprascapular notch to supply supraspinatus and infraspinatus. The root of C7 continues to become the middle trunk; the roots of C8 and T1 join to form the lower trunk. The upper trunk divides into its anterior and posterior divisions just above the clavicle. The middle and lower trunks divide deep to the clavicle. The anterior divisions of the upper and middle trunks join to form the lateral cord, which gives off the lateral pectoral nerve before dividing into the musculocutaneous nerve and the lateral head of the median nerve. The anterior division of the lower trunk forms the medial cord and may be supplemented by a branch from the anterior division of the middle trunk. The medial cord gives off the medial pectoral nerve, the medial cutaneous nerve of arm and medial cutaneous nerve of forearm before dividing into the medial head of the median nerve and the ulnar nerve. The posterior divisions join to form the posterior cord, branches of which are the superior and inferior subscapular nerves, the thoracodorsal nerve and the axillary nerve, before continuing as the radial nerve ( Fig. 37.2 ).

Fig. 37.2, The brachial plexus.

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